The purpose of this study is to evaluate the developmental course of psychopathology in the offspring of bipolar mothers. Psychopathology is conceptualized both in more traditional diagnostic categories and broad- based assessments of problem behaviors. The focus was on the two children of 26 families who had bipolar mothers. Families were seen at three points in the child's lifetime. At each time period, diagnostic and broad-based observations and self- and parent-reports were administered. There are contrasts between the diagnostic and broad-base developmental assessments in early childhood suggest that problem behaviors are best represented by broad-based assessments. That is, this group of 'at risk' children manifest problems that are of concern, but do not fit into the diagnostic groupings typically used for assessing childhood psychopathology. In middle childhood through adolescence, diagnostic assessments reflect the high level of psychological dysfunction found in this group.